Abilities » Power Connect
Is Deoxys EX's "Power Connect" Ability stackable?
Yes, it is.
Source: Plasma Freeze FAQ (2013-05-16), TPCi Rules Team (2013-05-16)

Relevant cards

Note: All applicable cards may not be listed below.
BW9_111
BW9_53
BWP_BW82
BWP_BW82